The instant invention relates to actuated valve assemblies which are operative for automatically shutting off the water and gas supplies to a hot water heater upon detection of a water leak from the hot water tank. More particularly, the instant invention relates to a valve assembly and water sensitive actuator therefor which effects shutting off of the water and gas supplies without any external supply of electricity.
Actuators and valves for automatically shutting off the water supply to a hot water tank upon detection of a water leak are well known in the art. In this regard, the U.S. Patents to Carver et al U.S. Pat. No. 2,798,503 and Maxfield U.S. Pat. No. 3,920,031 represent the closest prior art to the subject invention of which the applicant is aware. The U.S. Patent to Carver discloses a leak responsive actuator for cutting off the water supply to a water heater. A spring actuated valve is inserted into the cold water supply line and is connected by a cable to a water softenable latch disposed in a drip tray located beneath the water heater base. The spring actuated valve is normally biased to a closed position by the spring but is maintained in a normally open position by the cable and latch. When the latch is exposed to water, such as when the water heater tank ruptures, the water collected in the drip pan dissolves or softens the latch material thus releasing the cable and allowing the spring actuated valve to close the water supply line. The U.S. Patent to Maxfield discloses a similar device including a check valve and a spring biased actuator. The actuator includes a water dissolvable material which releases a spring biased plunger when exposed to water. The movement of the plunger actuates closing of the check valve. While each of the above-described devices is suitable for automatically shutting off the water to the water heater when a leak is detected, there is an apparent lack of any practical teaching for automatically shutting off the gas supply to the water heater. Although the damage caused by water leaking from the supply line can be substantial, the greater risk factor in terms of human injury can be the natural gas which may subsequently leak from the gas supply line when the pilot light is extinguished from the rising water level, or otherwise. When the pilot light is extinguished, gas may continue to leak from the pilot source, and/or the main burner. In some cases, where the water level rises, the natural gas can bubble up through the water and collect in the interior of the heater unit, which could potentially cause an explosion in the unit. Alternatively, if the tank empties and the pilot is not extinguished, the heat control system will continuously call for heat, and the main burner will run unchecked causing potentially dangerous overheating of the unit. Accordingly, there is believed to be a need for a simple and effective valve assembly for automatically shutting off both the water and gas supplies to a heated water vessel upon the detection of a water leak from the vessel.
In this regard, the present invention provides a valve assembly which is operative for automatically shutting off both a water supply line and gas supply line to a gas-fired hot water vessel upon detection of a water leak from the water vessel. The valve assembly is connected in the cold water supply line and generally includes a valve body, a valve member which is spring biased to a normally closed position, and a water softenable latch which maintains the valve member in an open position against the bias of the spring. The valve assembly is preferably mounted in a drip pan positioned under the water vessel such that water leaking from the water vessel will accumulate in the drip pan and eventually submerge at least a portion of the valve assembly. Upon contact with water accumulated in the drip pan, the water softenable latch will dissolve, or at least partially soften, and release the valve member thereafter moving from its open position to its closed position to cut off water supply through the valve body. In connection with shutting off of the gas supply, a formation on the valve member engages an electrical contact assembly attached to the valve body as the valve member moves from the open to closed position. The contact assembly is wired into the power circuit of an electromagnetic valve actuator of the gas supply control valve that controls gas flow to the water vessel burner. Engagement of the formation with the contact assembly temporarily opens the contact circuit and temporarily disrupts the flow of power to the electromagnetic valve actuator causing the associated solenoid to be released and the gas valve to be closed.
More specifically, the valve assembly includes a valve body having an interior fluid passage, an inlet arm and an outlet arm which are in fluid communication with said fluid passage. The inlet arm is connected to the water supply line and the outlet arm is connected to a water inlet line of the hot water vessel. The valve assembly further includes a valve member slidably received within a separate leg portion depending outwardly from the valve body. A cap is received over the open terminal end of the leg portion, and a tail portion of the valve member extends outwardly through an opening the cap. The valve member is slidably movable within the leg portion of the valve body between an open position wherein a head portion of the valve member is substantially entirely positioned within the leg portion of the valve body allowing water to flow through the fluid passage in the valve body, and a closed position wherein a head portion of the valve member extends into the valve body and matingly engages with a valve seat located within the fluid passage to prevent water from flowing through the valve body. As generally indicated hereinabove, a compression spring is captured between the valve member and the valve body for normally biasing the valve member to the closed position. The water softenable latch is coupled between the valve member and the leg portion of the valve body for normally holding the valve member in the open position against the bias of the spring. The contact assembly comprises a pair of contact members normally biased to a closed circuit condition. In the preferred embodiment, the contact members include leg portions which are snap received into a groove in the exterior tail portion of the valve member. In their normal mounted position, the contact members are in engagement and define a closed circuit. However, when the valve member moves from the open position to the closed position, the legs of the contact elements are forced out of the groove and moved temporarily apart thus opening the circuit, disrupting power to the electromagnetic valve actuator, and closing the gas supply valve.
Accordingly, among the objects of the instant invention are: the provision of a safety device for automatically shutting off the water and gas supply to a hot water heater upon detection of a water leak from the hot water tank; the provision of a valve assembly including a water softenable latch which triggers automatic cut-off of the water and gas supplies without any external supply of electricity; the provision of a valve assembly which generally includes a valve body, a valve member which is spring biased to a normally closed position, and a water softenable latch which maintains the valve member in an open position against the bias of the spring; the provision of such a valve assembly wherein upon contact with water, the water softenable latch will soften and release the valve member to move from its open position to its closed position to cut off water supply through the valve body; the provision of a valve assembly wherein an electrical contact assembly is attached to the valve assembly and is wired into the power circuit of the electromagnetic valve actuator of the gas supply control valve that controls gas flow to the water vessel burner; the provision of such a valve assembly wherein a formation on the valve member engages the electrical contact assembly as the valve member moves from the open to closed position and such engagement temporarily opens the contact circuit and temporarily disrupts the flow of power to the electromagnetic actuator causing the gas valve to be closed.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.